[gimp] (20 commits) Non-fast-forward update to branch wip/nielsdg/g-object-notify

[Michael Natterer <mitch src gnome org>]

The branch 'wip/nielsdg/g-object-notify' was changed in a way that was not a fast-forward update.
NOTE: This may cause problems for people pulling from the branch. For more information,
please see:

 https://wiki.gnome.org/Git/Help/NonFastForward

Commits removed from the branch:

  24923c5... Start using g_object_notify_by_pspec()

Commits added to the branch:

  0787510... libgimp: add gimp_procedure_add_(argument|return_value)_fro (*)
  2c4a8c8... libgimp, app: allow usage of GParamSpecString procedure arg (*)
  04598b1... plug-ins: use new gimp_procedure_add_*_from_property() in P (*)
  6a1df5b... libgimpwidgets: fix a copy-paste bug in function docs. (*)
  58b3ca8... plug-ins: port python-console to new API. (*)
  b6e6f0b... libgimp: gimplegacy not introspected anymore. (*)
  746a72b... Make sure to use % for constants (*)
  1dda601... Use "Returns:" to annotate return values (*)
  5f92ced... Add (nullable) if applicable (*)
  992f4b0... libgimp: add gimp_get_plug_in() which returns the GimpPlugI (*)
  3dd79f4... Revert "libgimp: move _gimp_read_expect_msg() back to gimp. (*)
  ad8dcff... libgimp: add _gimp_plug_in_read_expect_msg() (*)
  5cd0936... libgimp: fix gimp_procedure_add_*_from_property(). (*)
  5b8deb6... libgimp: make sure GimpProcedures always get all their argu (*)
  20d04e0... app, libgimp: support normal GParamInt for plug-in procedur (*)
  eaf5c79... plug-ins: port pagecurl to the new API, to have a GUI plug- (*)
  e705ab0... libgimp: remove useless includes (*)
  38089bb... libgmp: more useless includes (*)
  910828b... app: better error reporting in gimp_pdb_dialog_run_callback (*)
  529aa74... Start using g_object_notify_by_pspec()

(*) This commit already existed in another branch; no separate mail sent